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J/ApJ/661/1119      Spectroscopy in the 25 Ori group    (Briceno+, 2007)

25 Orionis: a kinematically distinct 10 Myr old group in Orion OB1a. Briceno C., Hartmann L., Hernandez J., Calvet N., Vivas A.K., Furesz G., Szentgyorgyi A. <Astrophys. J., 661, 1119-1128 (2007)> =2007ApJ...661.1119B
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Radial velocities ; Equivalent widths Keywords: open clusters and associations: individual (Orion OB1) - stars: kinematics - stars: pre-main sequence Abstract: We report here on the photometric and kinematic properties of a well-defined group of nearly 200 low-mass pre-main-sequence stars, concentrated within ∼1° of the early-B star 25 Ori, in the Orion OB1a subassociation. We refer to this stellar aggregate as the 25 Orionis group. The group also harbors the Herbig Ae/Be star V346 Ori and a dozen other early-type stars with photometry, parallaxes, and some with IR excess emission, indicative of group membership. Description: We obtained low-resolution optical spectra of our candidate PMS stars with a variety of telescopes and instruments. The brighter stars (V~>16) were observed at the 1.5m telescope of the Whipple Observatory equipped with the FAST Spectrograph. For the fainter (V~<16) candidates in our photometric survey the bulk of the spectroscopic follow-up was done with the Hectospec multifiber spectrograph on the 6.5m MMT telescope at Mount Hopkins. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 82 78 Low-mass pre-main sequence members in our 25 Orionis and Ori OB1b Hectochelle fields
See also: J/AJ/131/2959 : Candidate low-mass PMS in 25 Orionis group (McGehee+, 2006) J/AJ/129/907 : New Ori OB1 members (Briceno+, 2005) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 3 I3 --- CVSO CIDA Variability Survey of Orion running number (1) 5- 6 I2 h RAh Hour of Right Ascension (J2000) 8- 9 I2 min RAm Minute of Right Ascension (J2000) 11- 15 F5.2 s RAs Second of Right Ascension (J2000) 17 A1 --- DE- Sign of the Declination (J2000) 18- 19 I2 deg DEd Degree of Declination (J2000) 21- 22 I2 arcmin DEm Arcminute of Declination (J2000) 24- 27 F4.1 arcsec DEs Arcsecond of Declination (J2000) 29- 33 F5.2 mag Vmag The V band magnitude 35- 38 F4.2 mag V-Ic The Johnson-Cousins V-Ic color index 40- 43 A4 --- SpT Spectral type; errors are 1 subclass (2) 45- 49 F5.1 0.1nm EWHal Low-resolution equivalent width of Halpha (2) 51- 53 F3.1 0.1nm EWLi ? Equivalent width of LiI line (6707AA) (2) 55- 60 F6.2 0.1nm EWHah High-resolution equivalent width of Halpha (3) 62- 65 F4.1 km/s RV Radial velocity (3) 67- 69 F3.1 km/s e_RV The 1sigma error in RV (3) 71- 74 F4.1 --- R The cross-correlation process R value (4) 76 A1 --- Type [CW] Classical or Weak T Tau star (5) 78- 82 A5 --- Loc Object location (25Ori or OB1b)
Note (1): Continuing the numbering sequence from Briceno et al. (2005, Cat. J/AJ/129/907); stars from that article have CVSO numbers ≤197. The newly identified young members of 25 Ori and Orion OB1b presented here start with object CVSO-198. Note (2): Measurements from low-resolution spectra (FAST, Hydra, Hectospec). Note (3): Measurements from the high-resolution Hectochelle spectra. Note (4): A measurement of the ratio of the peak of the cross-correlation to the estimated noise, and is therefore an indicator of the accuracy of the results (Tonry & Davis, 1979AJ.....84.1511T). Note (5): The classification is based on spectral dependent threshold W(Hα) following White & Basri (2003ApJ...582.1109W). Stars CVSO-200, 238 and 246 have no low-resolution spectra available yet. They were classified as T Tauri stars from the Hectochelle spectra based on the following criteria: having the appropriate magnitudes and colors, radial velocity within 1-σ of the peak of the velocity distribution for their location, peculiar Hα emission, either a blue-shifted absorption component to Hα or this line very strongly in emission (the later is the case for CVSO-238).
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 04-Apr-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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